1. Field of the Invention
The present invention relates to an auto-splice device for a bias cutter.
2. Description of the Related Art
A conventional auto-splice is shown in FIGS. 23 to 25. A sheet 3 taken from a discharge conveyer 2 of a supplier 1 (not shown) is manipulated by an end position control unit (EPC unit) 4 to guide one end of the sheet 3 to a cutting conveyer 5. The sheet whose length has been measured is cut by a cutting unit 6, and one end of a fabric 7 thus cut is caught and conveyed by a vacuum conveyance unit 8 so as to be readied for splicing to one end of a fabric 9 the other of which has already been spliced.
The fabric 9 which has been spliced is taken out by a take-out conveyor 10 and is then wound up by a take-up unit 11.
The length of the sheet 3 is measured by controlling a send-out roller 13 so as to send out the sheet 3 by a distance L.sub.1 while counting the pulses of an encoder 12 which is mounted on the sheet 3. The fabric 7 which has been cut is positioned in the widthwise direction of the fabric 9 by controlling the cutting conveyor 5 to move by a given distance L.sub.2 from the cutting line.
A rear end of the fabric 9 is stopped at a position spaced from a sensor 14 by a given distance L.sub.3, and the vacuum conveyance unit 8 is moved back to a position indicated by a signal output from a sensor 15 of the EPC unit 4 so that the vacuum conveyance unit 8 catches the fabric 7. The fabric 7 is then moved by a distance L.sub.4 so as to overlap the front end of the fabric 7 and the rear end of the fabric 9 by a predetermined amount.
The above-mentioned conventional device suffers from the following problems.
(1) Even though the sheet is controlled by the end position control unit (EPC unit) so as to be introduced to the cutting conveyor at a given location, the fabric which has been cut sometimes slides on the cutting conveyor, thereby moving laterally. Therefore, even though the vacuum conveyance unit is controlled in accordance with a sensor signal of the EPC unit, the front end of the fabric is not always correctly positioned with respect to the vacuum conveyance unit. As a result, the correct amount of overlapping is not achieved even though the fabric is conveyed over a calculated distance.
(2) Even though the front end of the fabric 7 is conveyed by the vacuum conveyance unit with accuracy, the rear end of the fabric sometimes moves laterally while the fabric is conveyed toward the take-out conveyor. As a result, a so-called dog ear may occur, that is, an inconsistency in the widthwise direction of the spliced portion.
Japanese Patent Unexamined Publication No. Hei 3-250133 discloses a device which cuts a sheet to form a fabric, lifts the fabric in its entirety and transfers it from the cutting position to a junction take-out conveyer, positions the fabric parallel to a fabric whose one end has already been spliced, and joins the fabrics by first overlapping ends of the fabrics by a predetermined amount.
Japanese Patent Unexamined Publication Nos. Hei-2-151426, Sho 52-112674, Sho 62-5844 and the like, disclose devices which cut a sheet to form a fabric, discharge the fabric from a cutting conveyer to a joining conveyer in a free state, and thereafter detect an end of the fabric with a sensor in an attempt to correctly position the fabric prior to splicing.
These conventional devices suffer from the following problems.
(3) The device disclosed by Japanese Patent Unexamined Publication No. Hei 3-205133 has a complex structure and requires extremely complex calculations to match the positions of the fabrics to be spliced.
(4) The devices disclosed by Japanese Patent Unexamined Publication Nos. Hei 2-151426, Sho 52-112674, Sho 62-5844, etc. also have complex structures and are limited in their ability to correct the position of the fabric. In particular, when a cutting angle is at an acute angle such as 45.degree. to 60.degree., it is actually impossible to correct the position of the fabric within an acceptable range.